Circulating noggin levels following treatment with denosumab or teriparatide in postmenopausal women with low bone mass.

OBJECTIVES: Noggin inactivates bone morphogenetic proteins (BMPs), possibly exerting negative effects on the skeleton.We aimed to compare the effect of agents with opposite impact on bone turnover on noggin circulating levels. METHODS: In this observational, open label, non-randomized clinical study postmenopausal women with low bone mass were treated with either denosumab (n=30) or teriparatide (n=30). Serum samples were obtained at baseline, three and twelve months after treatment initiation. Prevalent fractures were recorded at baseline and lumbar spine bone mineral density (LS BMD) was measured at baseline and twelve months. Measured parameters included noggin, BMP-2, BMP-4, procollagen type 1 N-terminal propeptide (P1NP) and C-terminal cross-linking telopeptide of type 1 collagen (CTx). RESULTS: Noggin levels remained unchanged after either denosumab or teriparatide treatment. Baseline noggin levels were not different between women with vs. without previous anti-osteoporotic treatment, or between those with vs. without vertebral or non-vertebral fractures and were not correlated with age or LS BMD. At twelve months, noggin levels were positively correlated with P1NP within the denosumab (rs= 0.47; p=0.014), whereas negatively within the teriparatide group (rs= -0.43; p=0.019). CONCLUSIONS: In postmenopausal women with low bone mass noggin levels were not correlated with bone parameters at any time point, except with P1NP at 12 months, and remained stable with both denosumab and teriparatide treatment.

Denosumab effects on serum levels of the bone morphogenetic proteins antagonist noggin in patients with transfusion-dependent thalassemia and osteoporosis.

INTRODUCTION: Noggin is an antagonist of bone morphogenetic proteins (BMPs) and has a strong effect on osteogenesis. Osteoporosis is a common complication of transfusion dependent beta-thalassemia (TDT) and denosumab has been recently emerged as a promising therapeutic option. This was a post hoc investigation of serum noggin levels among TDT patients with osteoporosis who participated in a randomized, placebo-control, phase 2b study. METHODS: Patients received either 60 mg denosumab (n = 32) or placebo (n = 31) every 6 months for 12 months. Noggin was measured, for the first time in thalassemia patients, at baseline and at 12 months, using a recently developed high sensitivity fluorescent immunoassay. RESULTS: Both groups showed a significant increase in noggin serum levels (denosumab p < 0.001; placebo p < 0.0001). Interestingly, the increase was higher in the placebo group. Furthermore, we observed a strong correlation between noggin and wrist bone mineral density (r = -0.641, p = 0.002) only in the denosumab group. CONCLUSION: In conclusion, higher noggin levels reflected more BMP inhibition, since our assay detects free bioactive noggin, which in turn impaired bone formation in placebo group. Therefore, denosumab possibly regulates noggin and favours bone turnover in TDT patients with osteoporosis through a novel mechanism of action.

Noggin levels in nonalcoholic fatty liver disease: the effect of vitamin E treatment.

AIM: The evaluation of (a) noggin levels in patients with simple steatosis (SS) vs. nonalcoholic steatohepatitis (NASH) vs. controls, and (b) the effect of combined spironolactone plus vitamin E vs. vitamin E monotherapy on noggin levels in biopsy-proven patients with nonalcoholic fatty liver disease (NAFLD). METHODS: In the case-control study, 15 patients with SS, 16 with NASH, and 24 controls were included. In the randomized controlled trial, NAFLD patients were assigned to vitamin E (400 IU/d) or spironolactone (25 mg/d) plus vitamin E for 52 weeks. RESULTS: Noggin levels were lower in SS (5.8 ± 1.5 pmol/l) and NASH (8.7 ± 2.4 pmol/l) patients than in controls (13.7 ± 2.7 pmol/l; p for trend = 0.040), but were similar in SS and NASH patients. After adjustment for potential cofounders, log(noggin) remained different between groups. Log(noggin) levels similarly increased post-treatment in both groups: log(noggin) was not different between groups (p = 0.20), but increased within groups over time (p < 0.001), without a significant group × time interaction (p = 0.62). Log(noggin) significantly increased at month 2 post-treatment (p = 0.008 vs. baseline) and remained stable thereafter. CONCLUSIONS: Lower noggin levels were observed in NAFLD patients than in controls. Noggin levels increased similarly by either combined low-dose spironolactone plus vitamin E or vitamin E monotherapy. TRIAL REGISTRATION: NCT01147523.

Increased sclerostin serum levels associated with bone formation and resorption markers in patients with immobilization-induced bone loss.

CONTEXT: Sclerostin, a Wnt signaling antagonist on the osteoblasts produced by osteocytes, is regulated by mechanical strain and is implicated in the pathogenesis of disuse bone loss. There are no data on sclerostin in humans. OBJECTIVE: The aim of the study was to evaluate sclerostin in patients immobilized after stroke, compared with control subjects, and to analyze its relationship with markers of bone formation and resorption. DESIGN: This was a cross-sectional study. SETTING AND PATIENTS: We studied 40 postmenopausal women immobilized after a single episode of stroke 6 months or longer after onset, and 40 postmenopausal women from the general community. Bone status was assessed by quantitative ultrasound measurements at the calcaneus. Bone alkaline phosphatase (b-AP), carboxy-terminal telopeptide of type I collagen (CrossLaps), and sclerostin were evaluated by ELISA. We also used ELISA to measure serum levels of Dickkopf-1, another soluble inhibitor of Wnt/beta-catenin signaling, highly expressed by osteocytes. RESULTS: Immobilized patients had higher sclerostin serum levels (median 0.975 ng/ml; 25th to 75th percentiles 0.662-1.490) than controls (median 0.300 ng/ml; 25th to 75th percentiles 0.165-0.400: P < 0.0001) and an increased bone turnover with a more significant rise in bone resorption (CrossLaps) than formation (b-AP) markers. Sclerostin correlated negatively with b-AP (r = -0.911; P < 0.0001) and positively with CrossLaps (r = 0.391; P = 0.012). Dickkopf-1 did not significantly differ between the groups. Patients also had quantitative ultrasound measurements index lower than controls (P < 0.001). CONCLUSIONS: This study shows for the first time that long-term immobilized patients present hypersclerostinemia associated with reduced bone formation, and suggests that sclerostin could be a link between mechanical unloading and disuse osteoporosis in humans.

Circulating NT-proCNP predicts sepsis in multiple-traumatized patients without traumatic brain injury.

OBJECTIVES: C-type natriuretic peptide (CNP), a member of the natriuretic peptide family, is produced in vascular endothelium. We assessed the accuracy of natriuretic (NT)-proCNP, the N-terminal fragment of the C-type natriuretic peptide precursor, in predicting development of sepsis in multiple-traumatized patients with/without traumatic brain injury verified by computed tomography. DESIGN: Retrospective clinical study. SETTING: Level II trauma center. PATIENTS: Three patient groups were stratified according to computed tomography results: isolated traumatic brain injury (n = 20), multiple-traumatized with traumatic brain injury (n = 26) and multiple-traumatized without traumatic brain injury (n = 26). During 13 days after multiple trauma, 37 (51%) patients developed sepsis. MEASUREMENTS AND MAIN RESULTS: Circulating plasma NT-proCNP levels were measured daily (days 0-13) in all patients. Without any retrospective stratification of trauma patients, plasma NT-proNCP levels did not differ in septic (n = 37) and nonseptic (n = 35) patients (p = .505). Between days 2 and 6 posttrauma, there was a significant (p = .002) increase of circulating NT-proCNP in multiple-traumatized patients without traumatic brain injury who developed sepsis (n = 19) compared with nonseptic multiple-traumatized patients without traumatic brain injury. Conversely, in septic patients either with traumatic brain injury alone or with multiple trauma and traumatic brain injury, the NT-proCNP showed a trend toward lower levels than in nonseptic patients. Prediction of sepsis (receiver-operating characteristic test) from days 2 to 6 after multiple trauma by NT-proCNP in patients without traumatic brain injury was accurate with an area under the curve of 0.84 +/- 0.03. The optimal cutoff value of 2.3 pmol/L produced sensitivity of 84% to 96% and specificity of 61% to 91% from day 2 to 6 after trauma. CONCLUSIONS: Our data showed that the levels of circulating NT-proCNP between multiple-traumatized patients without traumatic brain injury who do and do not develop sepsis are distinctly different. Plasma NT-proCNP concentration can potentially serve as an accurate predictor of sepsis in this cohort of patients.

Plasma N-terminal pro-B-type natriuretic peptide concentration helps to predict survival in dogs with symptomatic degenerative mitral valve disease regardless of and in combination with the initial clinical status at admission.

OBJECTIVES: Although mitral valve disease (MVD) is the most common canine heart disease, readily available prognostic markers of the disease are still lacking. The aim of this study was to evaluate the comparative ability of N-terminal pro-B-type natriuretic peptide plasma concentration (NT-proBNP) and various echocardiographic variables to predict outcome in dogs with MVD. ANIMALS, MATERIALS AND METHODS: Seventy-four dogs with ISACHC classes 2 and 3 MVD (Groups A and B, respectively) were prospectively recruited. NT-proBNP and several echo-Doppler variables at inclusion were compared as predictors of outcome at 6 months in 54/74 dogs. RESULTS: NT-proBNP was significantly higher in Group B than in Group A (P<0.0001), and was the only tested variable significantly different between survivor and non-survivor dogs in both groups (P<0.05). In the whole canine population, a threshold of 1500 pmol/L could discriminate survivor from non-survivor dogs with a sensitivity and specificity of 80% and 73%, respectively. When combining ISACHC class with NT-proBNP levels, a cut-off of 1265 pmol/L was predictive of survival in Group A, whereas the cut-off was 2700 pmol/L for Group B. CONCLUSIONS: NT-proBNP is correlated with MVD severity and could be used in combination with clinical status to predict cardiac outcome.

The circulating calcification inhibitors, fetuin-A and osteoprotegerin, but not matrix Gla protein, are associated with vascular stiffness and calcification in children on dialysis.

BACKGROUND: Vascular calcification occurs in the majority of patients with chronic kidney disease, but a subset of patients does not develop calcification despite exposure to a similar uraemic environment. Physiological inhibitors of calcification, fetuin-A, osteoprotegerin (OPG) and undercarboxylated-matrix Gla protein (uc-MGP) may play a role in preventing the development and progression of ectopic calcification, but there are scarce and conflicting data from clinical studies. METHODS: We measured fetuin-A, OPG and uc-MGP in 61 children on dialysis and studied their associations with clinical, biochemical and vascular measures. RESULTS: Fetuin-A and OPG were higher and uc-MGP lower in dialysis patients than controls. In controls, fetuin-A and OPG increased with age. Fetuin-A showed an inverse correlation with dialysis vintage (P = 0.0013), time-averaged serum phosphate (P = 0.03) and hs-CRP (P = 0.001). Aortic pulse wave velocity (PWV) and augmentation index showed a negative correlation with fetuin-A while a positive correlation was seen with PWV and OPG. Patients with calcification had lower fetuin-A and higher OPG than those without calcification. On multiple linear regression analysis Fetuin-A independently predicted aortic PWV (P = 0.004, beta = -0.45, model R(2) = 48%) and fetuin-A and OPG predicted cardiac calcification (P = 0.02, beta = -0.29 and P = 0.014, ss = 0.33, respectively, model R(2) = 32%). CONCLUSIONS: This is the first study to define normal levels of the calcification inhibitors in children and show that fetuin-A and OPG are associated with increased vascular stiffness and calcification in children on dialysis. Higher levels of fetuin-A in children suggest a possible protective upregulation of fetuin-A in the early stages of exposure to the pro-calcific and pro-inflammatory uraemic environment.

The imbalance between osteoprotegerin and cathepsin K in the serum of patients with longstanding rheumatoid arthritis.

Osteoprotegerin (OPG) and soluble receptor activator of NF-kappa B ligand (sRANKL) together regulate the bone metabolism among other cytokines, whereby cathepsin K has a potent collagen-degrading activity. An imbalance of this system may be partly responsible for the skeletal complications of RA. Expanding on a previous study, we investigated the relationship between OPG, sRANKL and cathepsin K levels in the serum of patients with longstanding RA. We measured serum levels of OPG, sRANKL and cathepsin K of 100 patients with active, longstanding RA. We detected elevated serum levels of cathepsin K (median 54.8 pmol/l) and OPG (median 4.8 pmol/l), but normal sRANKL levels (median 0.2 pmol/l). Cathepsin K did not show a correlation with the overexpressed OPG (P=0.64) and sRANKL (P=0.81). The radiological destruction correlates significantly with cathepsin K (P=0.004) and OPG (P=0.007). We speculate that the increased levels of OPG are effective in compensating the action of sRANKL, but do not directly prevent bone degradation, as reflected by the elevated serum levels of cathepsin K.

Cathepsin K predicts femoral neck bone mineral density change in nonosteoporotic peri- and early postmenopausal women.

OBJECTIVE: Cathepsin K is a cysteine protease that plays an essential role in organic bone matrix degradation. The aim of our study was to seek correlation of serum cathepsin K levels and a change in bone mineral density (BMD) over a 3-year period in a population of healthy nonosteoporotic women. The secondary end points were the correlations of serum cathepsin K with cross-sectional BMD and with other serum bone turnover markers and age. DESIGN: In 43 healthy women aged 42 to 57 years, blood samples for determination of cathepsin K, osteocalcin, bone alkaline phosphatase, C-terminal cross-linking telopeptide of type I collagen, osteoprotegerin, and nuclear factor kappaB ligand were collected at the time of the first BMD measurement. BMD measurements were repeated after 3 years. RESULTS: We found a moderate negative correlation of serum cathepsin K levels with change in femoral neck BMD, but none with change in spinal BMD. There were no significant correlations between cross-sectional BMD of the spine or femoral neck and serum levels of cathepsin K. Serum levels of cathepsin K were not significantly correlated with any bone turnover markers studied or with age. CONCLUSIONS: Serum cathepsin K does not seem to represent a surrogate for bone turnover markers used at present, but it might be useful as a predictor of cortical bone loss.

Bisphosphonate treatment does not affect serum levels of osteoprotegerin and RANKL in hypercalcemic cancer patients.

Bisphosphonates are the standard treatment for hypercalcemia of malignancy. We hypothesized that bisphosphonate treatment and the subsequent fall in serum calcium might induce changes in the RANK/RANKL/OPG system, which plays a pivotal role in the regulation of bone resorption. Soluble RANKL and OPG levels were measured in the serum of 15 hypercalcemic patients at baseline and on 5 consecutive days following treatment with the amino-bisphosphonate ibandronate. At day 0, the median soluble OPG level was elevated (p=0.0021) in the hypercalcemic group as compared to normal controls, while the median serum RANKL level was not significantly different. Ibandronate treatment and the resulting decrease (p<0.0001) in serum calcium levels did not affect the serum concentrations of OPG, serum RANKL, or the serum RANKL/OPG ratio. In comparison with day 0, these factors did not change significantly at any time-point analyzed.

Serum cathepsin K levels of patients with longstanding rheumatoid arthritis: correlation with radiological destruction.

Cathepsin K is a cysteine protease that plays an essential role in osteoclast function and in the degradation of protein components of the bone matrix by cleaving proteins such as collagen type I, collagen type II and osteonectin. Cathepsin K therefore plays a role in bone remodelling and resorption in diseases such as osteoporosis, osteolytic bone metastasis and rheumatoid arthritis. We examined cathepsin K in the serum of 100 patients with active longstanding rheumatoid arthritis. We found increased levels of cathepsin K compared with a healthy control group and found a significant correlation with radiological destruction, measured by the Larsen score. Inhibition of cathepsin K may therefore be a new target for preventing bone erosion and joint destruction in rheumatoid arthritis. However, further studies have to be performed to prove that cathepsin K is a valuable parameter for bone metabolism in patients with early rheumatoid arthritis.

Effect of systemic glucocorticoid therapy on bone metabolism and the osteoprotegerin system in patients with active Crohn's disease.

BACKGROUND AND AIMS: Osteoporosis may occur in 25-30% of patients with Crohn's disease. Its pathogenesis is not completely understood. Both systemic inflammation in acute disease and treatment with systemic glucocorticoids have been implicated. The aim of the present study was to investigate changes in bone density and biochemical markers of bone metabolism before and during a 3-month period of high-dose glucocorticoid treatment for acute flare-up of Crohn's disease. METHODS: Twenty-five patients with active Crohn's disease requiring systemic glucocorticoid treatment (prednisolone, 60 mg/day) were investigated. Lumbar spine and femoral neck bone mineral densitometry was performed at baseline and again after 3 months. Clinical examinations including evaluation of the Crohn's disease activity index and measurement of the biochemical markers osteocalcin, deoxypyridinoline, osteoprotegerin and the soluble receptor activator of NF-kappaB ligand were performed prior to, and at 1, 2 and 12 weeks following steroid administration. RESULTS Median lumbar bone mineral density decreased significantly during the observation period by 1.04% from -0.84 (t score; range, -2.8 to +0.57) to -0.95 (range, -3.1 to +0.40; P = 0.022), while bone density of the total femur decreased by 2.9% from -0.83 (range, -2.61 to +1.86) to -0.90 (range, -2.65 to +0.19; P = 0.01). Serum levels of osteocalcin, a bone formation marker, and osteoprotegerin, an anti-resorptive cytokine produced by osteoblasts, decreased after the first 2 weeks of treatment and reached baseline levels after 3 months. No significant change was found for the bone resorption marker deoxypyridinoline, while soluble receptor activator of NF-kappaB ligand, a cytokine promoting bone resorption, tended to increase during steroid treatment. CONCLUSION: A decrease in bone mineral density in patients with Crohn's disease appears to result, at least in part, from a short-term effect of systemic glucocorticoid. Modulation of osteoclastogenesis by the receptor activator of NF-kappaB ligand/osteoprotegerin cytokine system and decreased osteoblastic function may be the underlying molecular basis.

Immunoassay for soluble RANKL (receptor activator of NF-kappaB ligand) in serum.

This paper describes a method for the direct measurement of human sRANKL (receptor activator of NF-kappaB ligand), a cytokine of the tumor necrosis factor superfamily, which is a key player in bone metabolism. Its role in the regulation of osteogenic disorders such as osteoporosis, Paget's disease and rheumatoid arthritis is being extensively discussed in the literature at present. We developed a highly specific, simple and reliable ELISA which allows the direct measurement of uncomplexed sRANKL in human serum. Assay characteristics such as analytical precision, sensitivity, interfering factors, sample stability and dilution linearity are shown. Reference values from healthy volunteers (n=57) were found to be between 0 and 2.7 pmol/l (10th-90th percentile) with a mean serum value of 1.3 pmol/l (median 0.9 pmol/l).

[Calcification marker matrix G1a protein in patients with hyperlipidemia]. / Der Kalzifikationsmarker Matrix-Gla-Protein bei Patienten mit Hyperlipidämie.

At the site of atherosclerotic plaque formation, proliferating vascular muscle cells express Matrix-Gla-protein (MGP) which depends on vitamin K and plays a regulatory role in tissue calcification. Measurements of MGP in serum showed significantly higher values in 66 patients with hyperlipidemia compared to healthy controls. MGP correlated with cholesterol, triglyceride, and low-density lipoprotein, but not with the adhesion molecule GMP-140. The evaluation of the patients' life and nutritional habits showed that nearly exclusively the patients who regularly consume fruit had low MGP values. Smokers had high MGP levels, three times higher than non-smokers. A decrease in MGP levels could be shown already three weeks after inpatient rehabilitation comprising therapeutic exercise and change in nutrition.